Metallic plate and recording tape cartridge

ABSTRACT

A metallic plate that is a structure of a release member, the release member being configured to be integrally rotatable with a reel accommodated in a case, and the release member moving a locking member from a locking position, at which the locking member locks rotation of the reel relative to the case, to an allowing position, at which the locking member allows rotation of the reel. The metallic plate comprises a touching surface that is to be touched by a distal end of a sliding protrusion portion that protrudes from the locking member; and a structure such that, if a plurality of the metallic plate are stacked in a plate thickness direction in a state in which the metallic plates are not attached to release members, the touching surface of each metallic plate is not in contact with any other of the metallic plates.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC 119 from Japanese PatentApplication, No. 2014-191759 filed Sep. 19, 2014, the disclosure ofwhich is incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a recording tape cartridge thatrotatably accommodates a single reel on which a recording tape such as amagnetic tape or the like is wound, and to a metallic plate thatstructures a release member provided in the recording tape cartridge.

2. Related Art

A recording tape cartridge that has been known heretofore rotatablyaccommodates a single reel, on which a recording tape such as a magnetictape or the like is wound, inside a case. This recording tape cartridgeenables a reduction in accommodation space during storage and may recordlarge volumes of data. This recording tape cartridge is equipped with alocking member, which is for locking the reel so as not to rotate insidethe case at times of non-use, and a release member, which is forreleasing the locking of the locking member at times of use.

During use of the recording tape cartridge, that is, during rotation ofthe reel, a spherical surface-shaped protrusion portion of the lockingmember and a flat surface-shaped touching surface of the release member,which are both resin members, slidingly contact one another.Accordingly, as disclosed in, for example, Japanese Patent ApplicationLaid-Open (JP-A) No. 2004-348839, in the light of increasing rotationspeeds aimed at shortening access times to desired recording positionsand data, a recording tape cartridge has been proposed heretofore inwhich a metallic plate that structures the touching surface is providedat the release member.

SUMMARY

However, when a metallic plate is provided at a release member andserves as a touching surface, if the touching surface is damaged (forexample, if the arithmetic mean roughness becomes 0.3 μm or more), thereis concern that behavior of the release member with respect to aprotrusion portion of a locking member may become disordered duringrotation of the reel.

Then, if the behavior of the release member during the rotation of thereel is disordered, there is concern that the protrusion portion of thelocking member may receive, for example, diametric direction forcecomponents from the touching surface of the release member, and thatconsequently noise will be generated during the rotation of the reel.

Accordingly, the present invention provides a metallic plate that maysuppress damage to a touching surface that touches the locking member,and a recording tape cartridge that is provided with a release memberthat includes this metallic plate.

In order to achieve the object described above, a metallic plateaccording to a first aspect of the present invention is a structure of arelease member, the release member being configured to be integrallyrotatable with a reel accommodated in a case, and the release membermoving a locking member from a locking position, at which the lockingmember locks rotation of the reel relative to the case, to an allowingposition, at which the locking member allows rotation of the reel, themetallic plate including: a touching surface that is to be touched by adistal end of a sliding protrusion portion that protrudes from thelocking member; and a structure such that, if a plurality of themetallic plate that are not attached to release members are stacked in aplate thickness direction, the touching surface provided at eachmetallic plate is not in contact with any other of the metallic plates.

Further, a recording tape cartridge according to the present inventionincludes: a reel at which a recording tape is wound onto a reel hubwhose shape is a circular tube with a bottom portion, the reel beingrotatably accommodated in a case; a locking member that is provided inthe reel hub to be movable in an axial direction of the reel, thelocking member movable to a locking position, at which the lockingmember locks rotation of the reel, and an allowing position, at whichthe locking member allows rotation of the reel relative to the case; arelease member that is provided in the reel hub to be integrallyrotatable with the reel, the release member moving the locking memberfrom the locking position to the allowing position when the releasemember is pushed from an outer side of the case; a sliding protrusionportion that protrudes from the locking member toward the side thereofat which the release member is disposed; and a metallic plate accordingto claim 1, the metallic plate being a structure of the release member.

According to the present invention, damage to a touching face, whichtouches a locking member, of a metallic plate that structures a releasemember provided in a recording tape cartridge may be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described in detail basedon the following figures, wherein:

FIG. 1A is a perspective view showing a recording tape cartridge inaccordance with an exemplary embodiment of the present invention, viewedfrom above;

FIG. 1B is a perspective view showing the recording tape cartridge inaccordance with the exemplary embodiment of the present invention,viewed from below;

FIG. 2 is a sectional diagram showing a reel of the recording tapecartridge in accordance with the exemplary embodiment of the presentinvention when locked;

FIG. 3 is a sectional diagram showing the reel of the recording tapecartridge in accordance with the exemplary embodiment of the presentinvention when locking is released;

FIG. 4 is an exploded perspective view showing a locking member thatstructures the recording tape cartridge in accordance with the exemplaryembodiment of the present invention and a rotary shaft of a drivedevice, viewed from above;

FIG. 5 is an exploded perspective view showing the locking member thatstructures the recording tape cartridge in accordance with the exemplaryembodiment of the present invention, viewed from below;

FIG. 6 is an exploded perspective view showing a metallic plate andclutch member that structure the recording tape cartridge in accordancewith the exemplary embodiment of the present invention;

FIG. 7 is a sectional diagram showing a partial magnification of a statein which the metallic plate that structures the recording tape cartridgein accordance with the exemplary embodiment of the present invention isassembled to the clutch member;

FIG. 8 is a sectional diagram showing a situation in which a pluralnumber of the metallic plate that structures the recording tapecartridge in accordance with the exemplary embodiment of the presentinvention are stacked;

FIG. 9A is a perspective view showing a variant example of the metallicplate that structures the recording tape cartridge in accordance withthe exemplary embodiment of the present invention;

FIG. 9B is a sectional diagram showing a situation in which a pluralnumber of the metallic plate according to the variant example thatstructure the recording tape cartridge in accordance with the exemplaryembodiment of the present invention are stacked; and

FIG. 10 is a sectional diagram showing a partial magnification ofanother variant example in the state in which the metallic plate thatstructures the recording tape cartridge in accordance with the exemplaryembodiment of the present invention is assembled to the clutch member.

DETAILED DESCRIPTION OF THE INVENTION

Herebelow, an exemplary embodiment relating to the present invention isdescribed in detail in accordance with the drawings. An arrow A shown inFIG. 1B represents a loading direction of a recording tape cartridge 10into a drive device (not shown in the drawings). For convenience ofdescription, the side indicated by arrow A is referred to as the frontside of the recording tape cartridge 10.

As shown in FIG. 1A and FIG. 1B, the recording tape cartridge 10 isprovided with a case 12. The case 12 is structured by an upper case 14and a lower case 16 being joined together. Specifically, the upper case14 is structured by a periphery wall 14B with a substantial frame shapestanding along an outer edge of a ceiling plate 14A with a substantiallyrectangular shape in plan view, and the lower case 16 is structured by aperiphery wall 16B standing along an outer edge of a floor plate 16Awith a shape substantially corresponding with the ceiling plate 14A. Thecase 12 is formed into a substantially rectangular box shape by theupper case 14 and the lower case 16 being joined, by ultrasonic welding,screw-fastening or the like, in a state in which the open end of theperiphery wall 14B is matched up with the open end of the periphery wall16B.

An aperture 18, which is angled with respect to the loading direction inplan view, is formed in the case 12 by the ceiling plate 14A, theperiphery wall 14B, the floor plate 16A and the periphery wall 16B beingrespectively cut away at a corner portion of the case 12 at the leadingside in the direction of loading into the drive device. A circular gearaperture 20 that penetrates through the floor plate 16A is provided at asubstantially central portion of the floor plate 16A. The gear aperture20 is for exposing a reel gear 42, which is described below, and thelike. An annular rib 22 (see FIG. 2) is provided at the floor plate 16A,protruding toward the interior side of the case 12 from an edge portionof the gear aperture 20. The annular rib 22 is for positioning of a reel30, which is described below.

A pair of positioning holes 24 and 26 open at a front end vicinity of anouter face of the floor plate 16A of the case 12. The pair ofpositioning holes 24 and 26 is provided in pocket shapes in projectionportions (not shown in the drawings) that stand to the interior side ofthe case 12 from the floor plate 16A. In a bottom view, the positioningholes 24 and 26 are disposed to be spaced apart from one another on animaginary line that is orthogonal to the loading direction. One of thepositioning holes 24, which is closer to the aperture 18, is formed in asubstantially square shape in bottom view. The one positioning hole 24is to contact the exterior of a positioning pin of the drive device.Another of the positioning holes 26, which is further from the aperture18, is formed as a long hole that extends along the imaginary line andwhose width corresponds to the diameter of another positioning pin.

Therefore, when the recording tape cartridge 10 is loaded in the drivedevice and the respective positioning pins are inserted into thepositioning holes 24 and 26, the recording tape cartridge 10 isprecisely positioned in horizontal (left-and-right and front-and-rear)directions in the drive device.

Regions of the floor plate 16A around the positioning holes 24 and 26serve as positioning surfaces 24A and 26A that are finished to a highersmoothness than other regions (design surfaces). When the positioningpins are inserted into the positioning holes 24 and 26, the positioningsurfaces 24A and 26A abut against positioning surfaces of the drivedevice, which are provided around the positioning pins. Therefore, therecording tape cartridge 10 is precisely positioned in the vertical(up-and-down) direction in the drive device.

The reel 30, which is described below, is singly accommodated inside thecase 12 to be rotatable. A magnetic tape T that serves as a recordingtape is wound onto the reel 30. A leader block 28 that serves as aleader member is attached to a distal end of the magnetic tape T. Whenthe recording tape cartridge 10 is not in use, the leader block 28 isaccommodated and retained at the inner side of the aperture 18 of thecase 12. Thus, the leader block 28 closes off the aperture 18 and blocksthe ingression of dust or the like into the case 12.

An engaging slot portion 28A is formed at the distal end of the leaderblock 28. When the magnetic tape T is to be pulled out inside the drivedevice, the leader block 28 is disengaged from the case 12 and guided toa take-up reel (not shown in the drawings) of the drive device by apull-out member that engages with the engaging slot portion 28A. An endface of the leader block 28 at the opposite side thereof from the sideat which the engaging slot portion 28A is disposed is formed as acircular arc face 28B. The leader block 28 is fitted into the take-upreel and the circular arc face 28B structures a portion of a take-upsurface onto which the magnetic tape T is taken up.

As shown in FIG. 2 to FIG. 4, the reel 30, which is fabricated of resin,is provided with a reel hub 32 that structures an axial center portionof the reel 30. The reel hub 32 is formed substantially in the shape ofa circular tube with a bottom, including a tube portion 34 and a bottomportion 36. The magnetic tape T is wound onto an outer periphery face ofthe tube portion 34. The bottom portion 36 closes off a lower portion ofthe tube portion 34. A lower flange 38 is provided extending to thediametric direction outer side from a vicinity of a lower end portion atthe bottom portion 36 side of the reel hub 32, coaxially and integrallytherewith.

An upper flange 40 (not shown in FIG. 4) is joined to an upper endportion of the reel hub 32. An outer diameter of the upper flange 40 isthe same as the outer diameter of the lower flange 38. A short tubeportion 40A is integrally formed at an axial center portion of the upperflange 40. An outer diameter of the short tube portion 40A correspondswith an inner diameter of the tube portion 34. In a state in which theshort tube portion 40A is fitted into an upper end vicinity of the tubeportion 34, the upper flange 40 is fixed to the reel hub 32, so as to becoaxial therewith, by ultrasonic welding.

Thus, a structure is formed in which the magnetic tape T is wound ontothe outer periphery face of the tube portion 34 of the reel hub 32 ofthe reel 30 between opposing faces of the lower flange 38 and the upperflange 40. Even though the upper flange 40 is provided, the tube portion34 is open to upward. Meanwhile, as shown in FIG. 1B and FIG. 5, thereel gear 42 is formed at an outer periphery vicinity of a lower face ofthe bottom portion 36 of the reel hub 32. The annular reel gear 42 iscoaxial with the reel 30 as a whole.

The reel gear 42 is formed to be meshable with a driving gear 108 thatis provided at the distal end of a rotary shaft 106 of the drive device.The rotary shaft 106 is described below. Portions of teeth of the reelgear 42 at the diametric direction outer sides thereof are connectedwith one another, from tooth height direction middle portions to toothbases, by a taper portion 43 that is continuous with the lower flange38.

As shown in FIG. 4, an annular engaging gear 44 is formed at an outerperiphery vicinity of the upper face of the bottom portion 36 of thereel hub 32. The engaging gear 44 serves as an engaging portion that iscoaxial with the reel 30 as a whole. The engaging gear 44 is formed onan annular seat portion 46 that projects a little from the upper face ofthe bottom portion 36. The engaging gear 44 is formed to be meshablewith a braking gear 66 of a locking member 60, which is described below.

A plural number of upright ribs 48 are provided at the diametricdirection outer side of the engaging gear 44, including the seat portion46. The upright ribs 48 are spaced equidistantly in the circumferentialdirection. Each of the upright ribs 48 is continuous with the innerperiphery face of the tube portion 34 and the upper face of the bottomportion 36, and runs along the axial direction of the reel 30. Becausethe upright ribs 48 are present, the engaging gear 44 is disposed at thediametric direction inner side relative to the reel gear 42. Thefunctioning of the upright ribs 48 is described together with thelocking member 60 below.

As shown in FIG. 2 to FIG. 5, a penetrating hole 50 is formedpenetrating through the bottom portion 36 of the reel hub 32 at an axialcenter portion of the bottom portion 36. A clutch boss portion 52 isprovided standing from the upper face of the bottom portion 36. Theclutch boss portion 52 is provided in a short tubular shape along anedge portion of the penetrating hole 50. The clutch boss portion 52 isdescribed together with a clutch member 84 below.

A reel plate 54 is coaxially and integrally provided by insert-moldingin the lower face of the bottom portion 36 of the reel hub 32, at theinner side of the reel gear 42. The reel plate 54 is an annular plateformed of a magnetic material. A through-hole 54A is formed at an axialcenter portion of the reel plate 54. An inner diameter of thethrough-hole 54A is slightly smaller than an inner diameter of thepenetrating hole 50.

As shown in FIG. 2 and FIG. 3, in the state in which the reel 30 isaccommodated in the case 12, the reel 30 rests on the annular rib 22 attimes of non-use. Specifically, outer side portions of the taper portion43 of the bottom portion 36 of the reel 30 abut against an upper endface of the annular rib 22. The upper end face of the annular rib 22 isformed as a taper surface 22A that corresponds with the taper portion43. Thus, movement of the reel 30 in the diametric direction isrestricted.

In this state, the reel 30 is disposed completely inside the case 12,with the reel gear 42, the reel plate 54 and the like being exposedthrough the gear aperture 20 (see FIG. 1B). That is, the reel gear 42faces outside the case 12 through the gear aperture 20 withoutprotruding lower than the outer face of the floor plate 16A.

Therefore, operation of the reel 30, which is to say chucking and rotarydriving, from outside the case 12 is possible. In the same state, anannular restricting rib 56, which is provided standing from the ceilingplate 14A, is inserted into an upper portion of the tube portion 34 ofthe reel 30. An outer periphery face of the restricting rib 56 is madeto be close to the inner periphery face of the short tube portion 40A ofthe upper flange 40. Thus, the restricting rib 56 prevents loosemovements of the reel 30 inside the case 12.

The recording tape cartridge 10 is also provided with the locking member60, which locks rotation of the reel 30 at times of non-use. As shown inFIG. 4, the locking member 60 includes a main body portion 62. The mainbody portion 62 is formed substantially in the shape of a circular tubewith an upper portion, which opens downward. The main body portion 62 isformed of a tube portion 62A, which is formed in a short tubular shape,and a disc portion 62B, which closes off the upper end of the tubeportion 62A. The outer diameter of the tube portion 62A is set to besmaller than an inner diameter of the engaging gear 44, and the innerdiameter of the tube portion 62A is set to be larger than an outerdiameter of the clutch boss portion 52.

A linking portion 64 that is formed in an annular shape is providedprotruding to the diametric direction outer side from an axial directionmiddle portion of an outer periphery portion of the main body portion 62(the tube portion 62A), over the entire circumference thereof. As shownin FIG. 5, the braking gear 66 is provided at a lower face of thelinking portion 64, over the entire circumference. That is, the brakinggear 66 is formed in an annular shape. The braking gear 66 is structuredto be meshable with the engaging gear 44 of the reel 30.

Inner end portions of teeth that structure the braking gear 66 areconnected with one another by the tube portion 62A. Outer end portionsof these teeth are disposed slightly to the diametric direction innerside relative to an outer edge of the linking portion 64. As is shown inFIG. 4, an annular reinforcing rib 68 is provided standing from theupper face of the linking portion 64, along an outer edge portionthereof. The reinforcing rib 68 assures stiffness of the linking portion64 (the braking gear 66).

As shown in FIG. 5, a sliding protrusion portion 70 is providedprotruding from an axial center portion of the lower face of the discportion 62B of the main body portion 62. A distal end portion of thesliding protrusion portion 70 is formed in a substantially sphericalsurface shape, so as to make substantial point contact with a metallicplate 100 (a touching surface 100A) of the clutch member 84, which isdescribed below. The distal end of the sliding protrusion portion 70 isdisposed slightly upward relative to the lower end face of the tubeportion 62A.

As shown in FIG. 4 and FIG. 5, a cross projection 72 is providedstanding from the upper face of the disc portion 62B. An insertion slot72A with a substantial cross shape in plan view is formed inside thecross projection 72. Penetrating holes 74 that penetrate through thedisc portion 62B in the plate thickness direction thereof are providedinside the insertion slot 72A. The penetrating holes 74 are formed asfour rectangular holes along the insertion slot 72A, excluding an axialcenter portion (an intersection portion) of the insertion slot 72A. Thatis, the penetrating holes 74 are each formed adjacent to the diametricdirection outer side of the sliding protrusion portion 70.

An annular rib 76 is provided at an upper end outer periphery portion ofthe main body portion 62. The upper face of the disc portion 62B betweenthe rib 76 and the cross projection 72 serves as a spring holdingsurface 78 against which one end portion of a compression coil spring82, which is described below, abuts. Thus, the locking member 60 isinsertedly provided inside the tube portion 34 of the reel hub 32, to besubstantially coaxial therewith and movable in an up-and-down direction(the axial direction of the reel 30).

That is, the locking member 60 is capable of assuming a locking positionand an allowing position by moving in the up-and-down direction. In thelocking position, the braking gear 66 is meshed with the engaging gear44 of the reel hub 32. In the allowing position, this meshing isreleased. A length of the tube portion 62A is determined such that alower end face thereof does not abut against the bottom portion 36 whenthe locking member 60 is disposed at the locking position (see FIG. 2).

As shown in FIG. 2 to FIG. 5, a cross rib 80 is provided protrudingdownward from the ceiling plate 14A of the case 12. The cross rib 80enters into the insertion slot 72A of the cross projection 72 of thelocking member 60. The cross rib 80 is formed in a detent shape in whichtwo thin plates intersect with one another so as to be orthogonal. Byengaging with the cross projection 72 (i.e., slot walls of the insertionslot 72A), the cross rib 80 blocks rotation of the locking member 60relative to the case 12.

Therefore, the locking member 60 may block rotation of the reel 30 bythe braking gear 66 of the locking member 60 meshing with the engaginggear 44 of the reel hub 32. The state in which the cross rib 80 entersinto the insertion slot 72A is maintained over the entire movementstroke of the locking member 60 in the up-and-down direction. Thus, thecross rib 80 is a structure that implements a function of guiding thedirection of movement of the locking member 60 in the up-and-downdirection.

Four projection pieces 80A are formed at a lower end portion of thecross rib 80. The projection pieces 80A are provided to protrude incorrespondence with the penetrating holes 74 of the locking member 60.Respective widths of the projection pieces 80A (lengths thereof in thediametric direction of the locking member 60) are set to correspond withlength direction dimensions of the penetrating holes 74. Thus, theprojection pieces 80A are structures that may enter into respectivelydifferent holes of the penetrating holes 74.

That is, the projection pieces 80A are disposed inside the insertionslot 72A when the locking member 60 is disposed at the locking position(see FIG. 2), and the projection pieces 80A penetrate through therespective penetrating holes 74 and protrude beyond the lower face ofthe disc portion 62B when the locking member 60 is disposed at theallowing position (see FIG. 3). Because the projection pieces 80A areprovided, an engagement amount of the cross rib 80 with the lockingmember 60 (an insertion depth) is increased, and tilting of the lockingmember 60 relative to the case 12 may be suppressed or prevented.

The locking member 60 is structured such that, when the locking member60 is disposed at the locking position, movement of the reel 30 in thediametric direction is restricted by the upright ribs 48 but, when thelocking member 60 is disposed at the allowing position, there is nodanger of interference between the locking member 60 and the uprightribs 48 rotating together with the reel 30. Accordingly, upper portionsof the upright ribs 48 are cut away such that the upright ribs 48 aredisposed close to the reinforcing rib 68 when the locking member 60 isdisposed at the locking position but separations between the uprightribs 48 and the reinforcing rib 68 are at least a predetermined valuewhen the locking member 60 is disposed at the allowing position.

Thus, the reel 30 is formed such that movement thereof is directlyrestricted by the case 12 (the annular rib 22 and the restricting rib56), and such that movement in the diametric direction relative to thecase 12 is restricted via the locking member 60 in a vicinity of theposition of the center of gravity. Therefore, the recording tapecartridge 10 may be reliably loaded even into a drive device that isdisposed in an upright arrangement (i.e., with the axial direction ofthe reel 30 in a horizontal direction).

The compression coil spring 82 is disposed between the spring holdingsurface 78 of the locking member 60 and the ceiling plate 14A, to serveas an urging member. The one end portion of the compression coil spring82 abuts against the spring holding surface 78 and another end portionof the compression coil spring 82 abuts against the ceiling plate 14A.An annular wall portion 58 is provided protruding from the ceiling plate14A at the outer side relative to the cross rib 80. The other endportion of the compression coil spring 82 is disposed at the inner sideof the annular wall portion 58 such that the other end portion of thecompression coil spring 82 does not become displaced in the diametricdirection.

The locking member 60 is urged downward by an urging force of thecompression coil spring 82. Thus, at usual times the braking gear 66 ismeshed with the engaging gear 44 and unintended rotation of the reel 30is blocked. In addition, the reel 30 is urged downward by the urgingforce via the locking member 60, and the reel 30 abuts against theannular rib 22 so as not to move loosely inside the case 12.

As shown in FIG. 2 to FIG. 5, the recording tape cartridge 10 is furtherprovided with the clutch member 84 that serves as a release member thatis operated from outside the recording tape cartridge 10 when the stateof locking of the reel 30 by the locking member 60 is to be released.The clutch member 84 is formed of a resin material such as polyamide(PA), polyacetal (POM) or the like. The clutch member 84 is disposedbetween the bottom portion 36 of the reel 30 and the locking member 60so as to close off the penetrating hole 50.

Describing this more specifically, the clutch member 84 includes aclutch main body 86 formed in a substantially circular shaft shape. Anouter diameter of the clutch main body 86, excluding a projectingportion 86A that is described below, is set to be slightly smaller thanthe inner diameter of the penetrating hole 50. The projecting portion86A is formed at an upper end portion of the clutch main body 86. Theprojecting portion 86A projects a little to the diametric directionouter side over the whole circumference of the clutch main body 86. Themetallic plate 100 that usually abuts against the sliding protrusionportion 70 of the locking member 60 is mounted at an upper end face ofthe clutch main body 86 including the projecting portion 86A. Details ofthe structure of the metallic plate 100 are described below.

A hollowed cavity 86B that opens downward is formed at an axial centerportion of the clutch main body 86. A flat lower end face around thehollowed cavity 86B serves as a pushing surface 86C. As is described indetail below, the clutch member 84 is a structure that, in the eventthat the pushing surface 86C is pushed upward, moves upward inopposition to the urging force of the compression coil spring 82 andmoves the locking member 60 to the allowing position.

The clutch member 84 is also provided with rotation restricting ribs 88that project to the diametric direction outer side relative to an outerperiphery face of the projecting portion 86A (of the clutch main body86). Three of the rotation restricting ribs 88 are provided, spacedequidistantly in the circumferential direction of the clutch main body86. Thus, the rotation restricting ribs 88 are arranged in a radiatingpattern in plan view. The rotation restricting ribs 88 are formedcontinuously over both an upper end face of the clutch main body 86 andthe outer periphery face of the projecting portion 86A. Thus, therotation restricting ribs 88 protrude upward and to the diametricdirection outer side.

The rotation restricting ribs 88 respectively enter into rotationrestricting slots (guide slots) 90 that are formed at an inner edgeportion of the clutch boss portion 52. The rotation restricting slots 90open upward at the upper end of the clutch boss portion 52. Thus, therotation restricting ribs 88 of the clutch member 84 are guided by therotation restricting slots 90 and movement of the clutch member 84 inthe up-and-down direction is enabled.

When the clutch member 84 moves upward and the locking member 60 isdisposed at the allowing position, the rotation restricting ribs 88maintain the state in which the same enter into the rotation restrictingslots 90. Therefore, the clutch member 84 is a structure that alwaysrotates integrally with the reel 30.

The clutch member 84 is further provided with seating ribs 92 thatfunction as a stopper portion for blocking a fall from the reel hub 32and allowing the metallic plate 100 to abut against the locking member60 disposed at the locking position. Three of the seating ribs 92 areprovided, at circumferential direction intermediate portions between therespective rotation restricting ribs 88 of the clutch main body 86.Thus, the seating ribs 92 are arranged in a radiating pattern in planview. The seating ribs 92 are formed continuously over both the upperend face of the clutch main body 86 and the outer periphery face of theprojecting portion 86A. Thus, the seating ribs 92 protrude upward and tothe diametric direction outer side.

The seating ribs 92 respectively enter into stopper slots 94 that areformed at the inner edge portion of the clutch boss portion 52. Thestopper slots 94 open upward at the upper end of the clutch boss portion52. Lower bottom faces that close off lower end portions of the stopperslots 94 serve as stopper faces 94A. When the locking member 60 isdisposed at the locking position, the clutch member 84 is positioned bylower end faces of the seating ribs 92 abutting against the stopperfaces 94A, such that the metallic plate 100 is usually caused to abutagainst the sliding protrusion portion 70.

Thus, because the rotation restricting ribs 88 and the seating ribs 92are provided separately from one another, the clutch member 84 is astructure in which a guiding function and a rotation restrictionfunction are separated from a function of restricting movement in theaxial direction of the reel 30. The clutch member 84 includes themetallic plate 100 at the upper end face of the clutch main body 86including the projecting portion 86A.

As shown in FIG. 6, three projection portions 96 for welding areintegrally provided protruding from the upper end face of the clutchmain body 86. The projection portions 96 are spaced equidistantly in thecircumferential direction and are disposed between the respectiverotation restricting ribs 88 and seating ribs 92. The metallic plate 100that, together with the clutch main body 86, structures the clutchmember 84 includes a disc portion 102 and ear portions 104. A sunkenportion 101 that is sunk downward is formed at an axial center portionof the disc portion 102. The ear portions 104 are provided extending tothe diametric direction outer side from outer periphery portions of thedisc portion 102.

Six of the ear portions 104 are provided in a radial pattern,equidistantly spaced in the circumferential direction. The ear portions104 are formed to enter between the respective rotation restricting ribs88 and seating ribs 92. To facilitate this entry, corner portions at thediametric direction inner sides of the rotation restricting ribs 88 andthe seating ribs 92 are cut away, forming chamfer portions 88A and 92A.Hole portions 105 through which the projection portions 96 can beinserted are formed in the ear portions 104. The hole portions 105penetrate through the ear portions 104 in the plate thickness directionthereof

Accordingly, the projection portions 96 are inserted into, of the sixhole portions 105 in the ear portions 104, three of the hole portions105 that are alternatingly disposed. In this state, the projectionportions 96 (principally, portions thereof that protrude beyond theupper face of the metallic plate 100) are each fused (welded) byultrasonic oscillations. Thus, the metallic plate 100 is fixed to theupper end face of the clutch main body 86, including the projectingportion 86A.

Annular portions 98 are coaxially and integrally formed at bases of theprojection portions 96. The annular portions 98 serve as referenceportions that support the metallic plate 100 from below. The annularportions 98 are formed to protrude upward from the upper end face of theclutch main body 86 in circular column shapes with larger diameters thanthe hole portions 105. Upper end faces of the annular portions 98 areformed to a higher precision than the upper end face of the clutch mainbody 86.

Thus, when the metallic plate 100 has been mounted to the clutch mainbody 86, a lower face 100B of the sunken portion 101 of the metallicplate 100 is not in contact with the upper end face of the clutch mainbody 86 (see FIG. 7). That is, the metallic plate 100 is supported onlyby the three annular portions 98. As a result, a position of themetallic plate 100 in the axial direction of the reel 30 relative to thepushing surface 86C of the clutch member 84 is positioned.

Protrusion heights of the projection portions 96 from the upper end faceof the annular portions 98 are specified so as to be larger than a platethickness of the metallic plate 100 (see FIG. 7) and such thatprotrusion heights of the projection portions 96 from the upper face ofthe metallic plate 100 (excluding the touching surface 100A) in thewelded state are lower than the rotation restricting ribs 88 and theseating ribs 92. Thus, a structure is formed in which, even if thelocking member 60 is tilted, the sliding protrusion portion 70 does notinterfere with the welded projection portions 96.

The metallic plate 100 is punched from a flat sheet of stainless steelby pressing using a punch and die. Thus, the disc portion 102 includingthe sunken portion 101 and the ear portions 104 including the holeportions 105 are formed integrally. The upper face inside the sunkenportion 101 formed in the disc portion 102 (a floor face) is finished toa mirror surface by mechanical machining (grinding, polishing or thelike), electroplating, coating or the like, to form the touching surface100A that abuts against the sliding protrusion portion 70 of the lockingmember 60.

The touching surface 100A of the metallic plate 100 is formed in acircular shape with a larger diameter than the distal end portion of thesliding protrusion portion 70. The surface roughness of the touchingsurface 100A is an arithmetic mean roughness (Ra) of not more than 0.1μm, specifically within a range of 0.01 μm to 0.1 μm. The platethickness of the metallic plate 100 is in a range from 0.05 mm to 0.7mm, is preferably in a range from 0.1 mm to 0.5 mm, and is morepreferably in a range from 0.2 mm to 0.3 mm.

The numerical range of the plate thickness of the metallic plate 100 isspecified to strike a balance between reducing plate thickness, which isdesired to assure a release stroke of the locking member 60 by theclutch member 84, and preventing bending, which is desired in regard toassurance of dimensional precision and ease of assembly. Moreover, if aplural number of the metallic plate 100 are stacked in the platethickness direction as illustrated in FIG. 8, during transport or thelike, the touching surface 100A of one of the metallic plates 100 at alower side is not in contact with the lower face 100B of the sunkenportion 101 of another of the metallic plates 100 at an upper side.

Moreover, even if a plural number of the metallic plate 100 are stackedin the plate thickness direction as illustrated in FIG. 8, an upperperipheral surface of a peripheral wall 101A, that forms the sunkenportion 101, of the metallic plate 100 at a lower side contacts with alower peripheral surface of a peripheral wall 101 A of the sunkenportion 101 of a metallic plate 100 at an upper side.

That is, a relationship between a diameter R1 of the touching surface100A inside the sunken portion 101, a diameter R2 of the lower face 100Bof the sunken portion 101 and a diameter R3 of an upper edge portion ofthe sunken portion 101 (i.e., the periphery wall 101A) is R1<R2<R3.Therefore, the touching surface 100A of the metallic plate 100 at thelower side does not touch against the lower face 100B of the sunkenportion 101 of the metallic plate 100 at the upper side.

In a state in which the rotation restricting ribs 88 and seating ribs 92of the clutch member 84 that is structured thus are inserted into therespectively different rotation restricting slots 90 and stopper slots94, the clutch main body 86 of the clutch member 84 is inserted throughthe penetrating hole 50 and the through-hole 54A. Hence, at usual times,the seating ribs 92 are retained in a state of abutting against thestopper faces 94A by the urging force of the compression coil spring 82that acts thereon via the locking member 60. In this state, the lowerend faces of the rotation restricting ribs 88 are slightly separatedfrom the bottom faces of the rotation restricting slots 90.

Further, in this state, the upper portion of the clutch member 84 andthe clutch boss portion 52 enter into the tube portion 62A of thelocking member 60. With the clutch boss portion 52, the tube portion 62Aforms a labyrinthine structure such that the ingression of dust throughthe penetrating hole 50 into the reel hub 32 (the case 12) issuppressed. In addition, while there is no functional need for theseating ribs 92 to enter into the stopper slots 94, the ingression ofdust into the reel hub 32 is suppressed by the seating ribs 92 enteringthe stopper slots 94.

As illustrated in FIG. 2 and FIG. 3, in association with an operation ofthe reel gear 42 meshing with the driving gear 108 provided at therotary shaft 106 that serves as an operation member at a drive device,the pushing surface 86C of the clutch member 84 is pushed by a releasesurface 114A of the rotary shaft 106 and moves upward. Thus, in thestate in which the reel gear 42 is meshed with the driving gear 108, theclutch member 84 is kept in the state in which the pushing surface 86Cabuts against the release surface 114A, and the locking member 60 isretained at the allowing position.

During rotation of the reel 30, there is no relative rotation betweenthe clutch member 84 rotating integrally with the reel 30 and the rotaryshaft 106 driving the reel 30. However, the clutch member 84 and thelocking member 60, that is non-rotatable relative to the case 12,relatively rotate. Therefore, the touching surface 100A of the metallicplate 100 and the distal end of the sliding protrusion portion 70 are insliding contact with one another.

A holding bolt 112 is provided at the rotary shaft 106. An upper endface of a head portion 114 of the holding bolt 112 serves as the releasesurface 114A that abuts against the pushing surface 86C of the clutchmember 84. A height of the release surface 114A may be adjusted bychanges to a threading amount of the holding bolt 112 in a threadedhole.

A magnet 110 is provided at the rotary shaft 106, for attracting andretaining the reel plate 54. The release surface 114A is finished toflatness equal to or flatter than an upper face of the magnet 110. Thus,a structure is formed in which a position of the release surface 114Arelative to the pushing surface 86C is determined in the axial directionof the reel 30 and the attitude of the clutch member 84 whose pushingsurface 86C is pushed by the release surface 114A is stable.

Now, operations of the recording tape cartridge 10 structured asdescribed above are described.

At times of non-use of the recording tape cartridge 10, the lockingmember 60 is disposed at the locking position by the urging force of thecompression coil spring 82, and the braking gear 66 is meshed with theengaging gear 44. Therefore, rotation of the reel 30 relative to thecase 12 is blocked. At these times, the reel gear 42 of the reel 30 isexposed through the gear aperture 20, and the clutch main body 86 of theclutch member 84 is inserted through the penetrating hole 50 and thethrough-hole 54A and faces the gear aperture 20.

When the magnetic tape T is to be used, the recording tape cartridge 10is loaded in the direction of arrow A into a bucket (not shown in thedrawings) of a drive device. When the recording tape cartridge 10 hasbeen loaded in the bucket to a predetermined depth, the bucket descends.The rotary shaft 106 of the drive device relatively moves toward thegear aperture 20 of the case 12 and retains the reel 30.

To be specific, the magnet 110 of the rotary shaft 106 attracts andretains the reel plate 54 without contact therewith, and the drivinggear 108 meshes with the reel gear 42 which is exposed through the gearaperture 20. In association with this meshing of the reel gear 42 withthe driving gear 108, the release surface 114A is abutted against thepushing surface 86C of the clutch member 84 and the rotary shaft 106pushes the clutch member 84 upward.

Accordingly, the clutch member 84 is moved to the upper side in theaxial direction of the reel 30 in opposition to the urging force of thecompression coil spring 82 by this pushing force, while the rotationrestricting ribs 88 of the clutch member 84 are guided by the rotationrestricting slots 90. As a result, the locking member 60 that isabutting against the metallic plate 100 of the clutch member 84 at thesliding protrusion portion 70 moves upward, and the meshing between thebraking gear 66 of the locking member 60 and the engaging gear 44 isreleased.

When the rotary shaft 106 relatively moves further upward, the reel 30is lifted upward together with the clutch member 84 and the lockingmember 60 against the urging force of the compression coil spring 82.When the locking member 60 reaches the allowing position, the lowerflange 38 is separated from the annular rib 22. In this manner, the reel30 rises inside the case 12 and becomes rotatable in a state ofnon-contact with the inner faces of the case 12.

The respective positioning pins of the drive device enter into thepositioning holes 24 and 26 of the case 12 when the recording tapecartridge 10 descends in the drive device, and the positioning surfacesof the drive device abut against the positioning surfaces 24A and 26A ofthe case 12. Thus, the recording tape cartridge 10 is positioned in thehorizontal directions and the vertical direction relative to the drivedevice.

Correspondingly, a pull-out pin (not shown in the drawings) of thepull-out member of the drive device is engaged with the engaging slotportion 28A of the leader block 28, and the leader block 28 isdisengaged from the case 12 and guided to the take-up reel of the drivedevice. The leader block 28 is fitted into the take-up reel and thecircular arc face 28B structures a portion of the take-up surface ontowhich the magnetic tape T is to be taken up.

In this state, when the leader block 28 rotates integrally with thetake-up reel, the magnetic tape T is taken up onto a reel hub of thetake-up reel while being pulled out from the case 12 through theaperture 18. At this time, the reel 30 of the recording tape cartridge10 is rotated in synchrony with the take-up reel by rotary force of therotary shaft 106, which is transmitted by the driving gear 108 that ismeshed with the reel gear 42.

Data is recorded onto the magnetic tape T and/or data recorded on themagnetic tape T is replayed by a recording/replay head that is disposedalong a predetermined tape path in the drive device. At this time, thesliding protrusion portion 70 of the locking member 60, rotation ofwhich relative to the case 12 is blocked, slidingly contacts themetallic plate 100 of the clutch member 84 that is rotating relative tothe case 12 together with the reel 30.

That is, the distal end of the sliding protrusion portion 70 that isconstituted of the resin material abuts against the touching surface100A in the sunken portion 101 of the metallic plate 100. Therefore,even if a rotation speed of the reel 30 (a conveyance speed of themagnetic tape T) is increased in order to shorten access times todesired recording positions and data, wear of the sliding protrusionportion 70 that is sliding in accordance with the rotation of the reel30 is suppressed compared to a clutch member (not shown in the drawings)that does not include the metallic plate 100.

Furthermore, the metallic plate 100 is supported only by the annularportions 98 that are coaxially and integrally formed at the bases of thethree projection portions 96 that are provided equidistantly in thecircumferential direction of the clutch main body 86. Therefore, theposition of the touching surface 100A of the metallic plate 100 in theaxial direction of the reel 30 is positioned accurately relative to thepushing surface 86C of the clutch member 84, and flatness of thetouching surface 100A relative to the pushing surface 86C is assured.Consequently, tilting of the touching surface 100A of the metallic plate100 relative to the sliding protrusion portion 70 of the locking member60 is suppressed or prevented, and the production of noise during therotation of the reel 30 is suppressed.

Even if the metallic plate 100 is plurally stacked during transport orthe like, the touching surface 100A of any of the metallic plates 100does not touch the lower face 100B of the sunken portion 101 of anotherof the metallic plates 100. Thus, the touching surface 100A is protecteduntil the metallic plate 100 is attached to the clutch main body 86 andassembled into the case 12. Therefore, damage (abrasion, scratches andthe like) to the touching surface 100A or suchlike is suppressed orprevented.

Therefore, during the rotation of the reel 30, disorder in the behaviorof the clutch member 84 relative to the sliding protrusion portion 70 ofthe locking member 60 is suppressed or prevented, and occurrences of thesliding protrusion portion 70 of the locking member 60 receiving, forexample, diametric direction force components from the touching surface100A of the metallic plate 100 are suppressed or prevented.Consequently, the production of noise during the rotation of the reel 30may be suppressed or prevented.

In particular, if the surface roughness of the touching surface 100A inthe sunken portion 101 of the metallic plate 100 is an arithmetic meanroughness of not more than 0.1 μm, disorder in the behavior of theclutch member 84 may be further suppressed or prevented. Thus, theproduction of noise during the rotation of the reel 30 may be even moreeffectively suppressed or prevented.

Moreover, if the surface roughness of the touching surface 100A in thesunken portion 101 of the metallic plate 100 is an arithmetic meanroughness of not more than 0.1 μm, there is a benefit in that thematerial of the metallic plate 100 need not be limited to expensivestainless steel. That is, the metallic plate 100 may be fabricated of ametallic material that is cheaper than stainless steel, and costsrelating to the metallic plate 100 may be reduced.

Then, when the magnetic tape T has been wound back to the reel 30 andthe leader block 28 is retained in the vicinity of the aperture 18 ofthe case 12, the bucket in which the recording tape cartridge 10 isloaded ascends. Correspondingly, the meshing between the reel gear 42and the driving gear 108 is released, the abutting of the releasesurface 114A against the pushing surface 86C of the clutch member 84 isreleased, and the clutch member 84 is moved downward together with thelocking member 60 by the urging force of the compression coil spring 82.

Consequently, the seating ribs 92 of the clutch member 84 abut againstthe stopper faces 94A and the braking gear 66 of the locking member 60meshes with the engaging gear 44. That is, the locking member 60 returnsto the locking position that blocks rotation of the reel 30 relative tothe case 12. Meanwhile, in association with the operation in which thelocking member 60 and the clutch member 84 are moved by the urging forceof the compression coil spring 82, the reel 30 also moves downward andreturns to the initial state in which the lower flange 38 abuts againstthe annular rib 22 while the reel gear 42 is exposed through the gearaperture 20. In this state, the recording tape cartridge 10 is ejectedfrom the bucket.

While the operation of the recording tape cartridge 10 relating to thepresent exemplary embodiment is as described above, the metallic plate100 may be formed as shown in FIG. 9A. That is, the metallic plate 1100includes an annular protrusion portion 103 around the touching surface100A of the disc portion 102. The protrusion portion 103 has a circulararc shape in cross section that protrudes in the plate thicknessdirection (upward in the case shown in FIG. 9B). When a plural number ofthis metallic plate 1100 are stacked, because of the protrusion portions103, the touching surface 100A of one of the metallic plates 1100 at alower side is not in contact with the lower face 100B of one of themetallic plates 1100 at an upper side.

To describe this in more detail, the curvature, height and the like ofthe protrusion portion 103 are suitably determined such that, when themetallic plate 1100 is plurally stacked in the plate thickness directionas shown in FIG. 9B, an upper surface of the protrusion portion 103 ofthe metallic plate 1100 at the lower side, excluding a peak portion103A, touches a diametric direction inner side edge portion (hereinafterreferred to as “the inner edge portion”) 103B and a diametric directionouter side edge portion (hereinafter referred to as “the outer edgeportion”) 103C that are formed at the metallic plate 1100 at the upperside by the formation of the protrusion portion 103 thereof

That is, a relationship between the diameter R1 of the touching surface100A, the diameter R2 of the lower face 100B (at the inner edge portion103B), a diameter R3 of the peak portion 103A, and a diameter R4 of theouter edge portion 103C is R1<R2<R3<R4. Hence, the touching surface 100Aof the metallic plate 1100 at the lower side does not touch against thelower face 100B of the metallic plate 1100 at the upper side.

If the protrusion portion 103 is formed continuously in the annularshape, there is an advantage in that there is no need for positioning ofthe protrusion portion 103 in the circumferential direction when themetallic plates 100 are being stacked. However, this is not limiting;structures are possible in which, for example, the protrusion portion103 is discontinuously and plurally formed along a predeterminedcircumference. Furthermore, the protrusion portion 103 is not limited toa structure that is formed in a circular arc shape in cross section butmay be formed in, for example, a substantial inverted “V” shape in crosssection. Further yet, the protrusion portion 103 may be a structure thatprotrudes downward.

As shown in FIG. 10, the clutch member 84 may be formed without theannular portions 98 being formed at the bases of the three projectionportions 96 provided at the clutch main body 86. When, for example, themetallic plate 100 illustrated in FIG. 6 to FIG. 8 is mounted at thisclutch member 84, it is sufficient if the lower face 100B of the sunkenportion 101 is in contact with the upper end face of the clutch mainbody 86. That is, the position of the metallic plate 100 in the axialdirection of the reel 30 relative to the pushing surface 86C of theclutch member 84 is positioned by the upper end face of the clutch mainbody 86 in this case.

In the metallic plate 100 according to the present exemplary embodiment,the hole portions 105 are provided at all six of the ear portions 104.Therefore, positioning of the hole portions 105 at the projectionportions 96 that would be required if the hole portions 105 wereprovided at only three of the ear portions 104 is not needed; theprojection portions 96 may be reliably inserted into the hole portions105 simply by the ear portions 104 being inserted between the rotationrestricting ribs 88 and the seating ribs 92. Therefore, even in anautomatic assembly process, the metallic plate 100 may be easilypositioned relative to the clutch member 84.

Hereabove, the metallic plate 100 and the recording tape cartridge 10according to the present exemplary embodiment have been described inaccordance with the drawings. However, the metallic plate 100 and therecording tape cartridge 10 according to the present exemplaryembodiment are not limited by the drawings. Suitable designmodifications may be applied within a scope not deviating therefrom inthe present invention.

For example, the number of the projection portions 96 is not limited tothree; four or more of the projection portions 96 may be formed. Thatis, it is sufficient that at least three of the projection portions 96and the hole portions 105 are formed. Further, the projection portions96 are not limited to the structures that are formed in substantiallycircular column shapes and may be formed in, for example, substantiallysquare column shapes or the like.

Although not shown in the drawings, the metallic plate 100 may beapplied to an alternative release member such as, for example, a releasepad with a substantially triangular shape in plan view in which threerelease projections protrude from above the reel gear 42, or the like.In the case of a release pad, a plane joining the three releaseprojections serves as the pushing surface. Further, if the ear portions104 are not formed at the metallic plate 100, due to an alternativeshape of the release member, it is sufficient if the hole portions 105are simply formed in the vicinity of a peripheral edge portion of themetallic plate 100.

In the present exemplary embodiment, the metallic plate 100 isstructured with the disc portion 102, but this is not limiting. Forexample, the metallic plate 100 may be a structure that includes a plateportion with a square shape, an equilateral triangle shape or the like.Further, the shape of the sunken portion 101, the protrusion portion 103or the like formed at the metallic plate 100 is a circular shape (or anannular shape) in plan view but this is not limiting; these may beformed in, for example, a polygonal shape or the like. Further yet,although the surface roughness of the touching surface 100A of themetallic plate 100 is set to an arithmetic mean roughness of not morethan 0.1 μm, this numerical value is not limiting.

In the present exemplary embodiment, the metallic plate 100 is astructure that is formed by punching, but a method of fabrication(machining) of the metallic plate 100 is not particularly limited.Further, the recording tape cartridge 10 according to the presentexemplary embodiment is a structure that includes the leader block 28 toserve as the leader member, but this is not limiting. As examples,although not shown in the drawings, a structure that includes a leaderpin with a substantially circular rod shape or a structure that includesa covering member that opens and closes the aperture 18 (a sliding doorthat moves along a predetermined straight line or circular arc, or thelike) may be formed.

The present exemplary embodiment has a structure in which the magnetictape T is used as the recording tape, but this is not limiting. It issufficient to understand the recording tape as being an informationrecording/replaying medium in a long, narrow tape shape at which datamay be recorded and recorded data may be replayed. The recording tapecartridge 10 according to the present exemplary embodiment is obviouslyapplicable to recording tapes of any recording/replay format.

What is claimed is:
 1. A metallic plate that is a structure of a releasemember, the release member being configured to be integrally rotatablewith a reel accommodated in a case, and the release member moving alocking member from a locking position, at which the locking memberlocks rotation of the reel relative to the case, to an allowingposition, at which the locking member allows rotation of the reel, themetallic plate comprising: a touching surface that is to be touched by adistal end of a sliding protrusion portion that protrudes from thelocking member; and a structure such that, if a plurality of themetallic plate are stacked in a plate thickness direction in a state inwhich the metallic plates are not attached to release members, thetouching surface of each metallic plate is not in contact with any otherof the metallic plates.
 2. The metallic plate according to claim 1,wherein the metallic plate includes a sunken portion, the touchingsurface being formed inside the sunken portion.
 3. The metallic plateaccording to claim 1, wherein the metallic plate includes a protrusionportion around the touching surface, the protrusion portion protrudingsubstantially in the plate thickness direction of the metallic plate. 4.The metallic plate according to claim 3, wherein the protrusion portionhas an annular shape.
 5. The metallic plate according to claim 1,wherein a surface roughness of the touching surface is an arithmeticmean roughness of at most 0.1 μm.
 6. A recording tape cartridgecomprising: a reel at which a recording tape is wound onto a reel hubwhose shape is a circular tube with a bottom portion, the reel beingrotatably accommodated in a case; a locking member that is provided inthe reel hub to be movable in an axial direction of the reel, thelocking member movable to a locking position, at which the lockingmember locks rotation of the reel, and an allowing position, at whichthe locking member allows rotation of the reel relative to the case; arelease member that is provided in the reel hub to be integrallyrotatable with the reel, the release member moving the locking memberfrom the locking position to the allowing position in the event that therelease member is pushed from an outer side of the case; a slidingprotrusion portion that protrudes from the locking member toward theside thereof at which the release member is disposed; and a metallicplate according to claim 1, the metallic plate being a structure of therelease member.
 7. The recording tape cartridge according to claim 6,wherein the release member comprises: at least three projection portionsthat fix the metallic plate to the release member, and at least threehole portions being formed in the metallic plate, the projectionportions being inserted into the hole portions and fused; and annularportions that support the metallic plate, the annular portions beingformed with larger diameters than the hole portions at bases of theprojection portions.